Positive electrode active material for rechargeable lithium battery, method of preparing same, and rechargeable lithium battery including same

Abstract

The present exemplary embodiments relate to a positive electrode active material, its manufacturing method, and a lithium secondary battery including the same. The positive electrode active material according to an exemplary embodiment is a metal oxide particle including: a metal oxide particle comprising a central portion and a surface portion located on the surface of the central portion, wherein, the metal oxide particle includes nickel, cobalt, manganese, and doping elements and is composed of a single particle, and the metal oxide particle includes a crystal phase of layered structure belonging to the R-3m space group on the surface, and an average grain size is 1550 Å or more.

What is claimed is: 
     
         1 . A positive electrode active material, comprising:
 a metal oxide particle comprising a central portion and a surface portion located on the surface of the central portion,   wherein, the metal oxide particle includes nickel, cobalt, manganese, and doping elements and is composed of a single particle, and   the metal oxide particle includes a crystal phase of layered structure belonging to the R-3m space group on the surface, and   an average grain size is 1,550 Å or more.   
     
     
         2 . The positive electrode active material of  claim 1 ,
 an average particle diameter D50 of the positive electrode active material is 3 μm or more.   
     
     
         3 . The positive electrode active material of  claim 1 ,
 the surface portion further includes a crystal phase of rock salt structure belonging to the Fm-3m space group with a thickness of 10 nm or less.   
     
     
         4 . The positive electrode active material of  claim 1 ,
 the doping element includes two or more selected from the group consisting of Al, Zr, Nb, Mo, W, Ti, Ce, Mg, P, V, Sr, and B.   
     
     
         5 . The positive electrode active material of  claim 1 ,
 a content of the doping element is a range of 0.0005 mole to 0.04 mole based on 1 mole of the total of the nickel, cobalt, manganese and doping elements.   
     
     
         6 . The positive electrode active material of  claim 1 ,
 the doping elements include Al and Zr.   
     
     
         7 . The positive electrode active material of  claim 6 ,
 a content of Al ranges from 0.001 mole to 0.04 mole, based on 1 mole of the total of the nickel, cobalt, manganese and doping elements.   
     
     
         8 . The positive electrode active material of  claim 6 ,
 a content of Zr ranges from 0.0016 mole to 0.0064 mole, based on 1 mole of the total of the nickel, cobalt, manganese and doping elements.   
     
     
         9 . The positive electrode active material of  claim 1 ,
 a content of nickel in the metal oxide particle is 0.8 mol or more, based on 1 mole of the total of the nickel, cobalt and manganese.   
     
     
         10 . The positive electrode active material of  claim 1 , wherein,
 it is included the single particle and a large particle composed of a secondary particle comprising a primary particle.   
     
     
         11 . The positive electrode active material of  claim 10 ,
 a mixing ratio of the single particle and the large particle, in weight ratio, ranges from 30:70 to 10:90.   
     
     
         12 . The positive electrode active material of  claim 11 ,
 the single particle and the large particle have different compositions.   
     
     
         13 . A manufacturing method of a positive electrode active material, comprising:
 preparing an aqueous solution of a metal salt containing nickel raw material, cobalt raw material, manganese raw material, and water;   obtaining metal hydroxide by supplying the aqueous solution of the metal salt to a co-precipitation reactor;   obtaining a lithium metal oxide by mixing the metal hydroxide, a lithium raw material, a doping raw material, and a boron compound and performing a first sintering step; and   performing a second sintering step by mixing the lithium metal oxide which is performed a first sintering step and a lithium raw material.   
     
     
         14 . The method of  claim 13 , wherein:
 in the step of obtaining the lithium metal oxide, the boron compound is mixed by adding in the range of 0.05 mole to 0.015 mole, based on 1 mole of a total of nickel, cobalt, manganese and doping elements in a final positive electrode active material.   
     
     
         15 . The method of  claim 13 , wherein:
 in the step of obtaining the lithium metal oxide, the mole ratio (Li/Me) of lithium (Li) to the entire metal (Me) excluding lithium is in the range of 1.01 to 1.1.   
     
     
         16 . The method of  claim 13 , wherein:
 the first sintering step is performed in the 820° C. to 890° C. range for 8 hours to 20 hours.   
     
     
         17 . The method of  claim 13 , wherein:
 the second sintering step is performed in the 600° C. to 800° C. range for 3 to 10 hours.   
     
     
         18 . The method of  claim 13 , wherein:
 in the second sintering step, the mixing amount of the lithium raw material ranges from 0.004 mole to 0.053 mole, based on 1 mole of the first sintered lithium metal oxide.   
     
     
         19 . The method of  claim 13 , wherein:
 the second sintering step is performed by adding and mixing at least one of a cobalt raw material, a zirconium raw material, a niobium raw material, an aluminum raw material, a titanium raw material, a manganese raw material, and a nickel raw material.   
     
     
         20 . The method of  claim 19 , wherein:
 in the second sintering step, an input amount of at least one of the cobalt raw material, the zirconium raw material, the niobium raw material, the aluminum raw material, the titanium raw material, the manganese raw material, and the nickel raw material is 0.001 mole to 0.02 mole, based on 1 mole of the first sintered lithium metal oxide.   
     
     
         21 . A lithium secondary battery comprising:
 a positive electrode comprising the positive electrode active material of any one of  claim 1 to claim 12 ;   a negative electrode; and   a non-aqueous electrolyte.